Chapter 6: Application Layer. Overview of Transport Layer, HTPP and Web, domain name, electrical Email, file transfer. Request and response messages, request and status lines, header format, domain name space, domain names and labels, query and response messages, header format

Bài giảng Mạng máy tính - Chương 2: Lớp ứng dụng (Application Layer) giúp các bạn làm quen với các khái niệm cũng như thực hiện các giao thức ứng dụng (mô hình dịch vụ lớp truyền tải, mô hình client-server, mô hình peer-to-peer).

This chapter is an introduction to the application layer. In the next eight chapters we introduce common client-server applications used in the Internet. In this chapter, we give a general picture of how a client-server program is designed and give some simple codes of their implementation. The area of network programming is a very vast and complicated one; it cannot be covered in one chapter. We need to give a bird’s-eye view of this discipline to make the contents of the next eight chapters easier to understand.

The primary duties of the transport layer, Layer 4 of the OSI model, are to transport and regulate the flow of information from the source to the destination, reliably and accurately. End-to-end control and reliability are provided by sliding windows, sequencing numbers, and acknowledgments To understand reliability and flow control, think of someone who studies a foreign language for one year and then they visit the country where that language is used. In conversation, words must be repeated for reliability and to speak slowly so that the meaning of the conversation is not lost, this is flow control. The transport...

Application Layer Filtering Application proxy firewalls are the most intelligent firewall architecture.